Driving and timing mechanism for fuel injection pump



J. M. BAILEY May 7, 1968 DRIVING AND TIMING MECHANISM FOR FUEL INJEGTONPUMP 3 Sheets-Sheet 1 Filed Dec.

m T Y E V R NA 5 M N H 0 J BY 71a; +7664 ATTORNEYS J. M. BAILEY May 7,I968 DRIVING AND TIMING MECHANISM FOR FUEL INJEC'ION PUMP 3 Sheets-Sheet2 Filed Dec. 9, 1966 I 2 Z? 42\ I40 90,9 ,36 40 mg INVENTOR JOHN M.BAILEY %w;% ayw a ATTORNEYS May 7, 1968 J. M. BAILEY 3,381,615

DRIVING AND TIMING MECHANISM FOR FUEL INJECTON PUMP Filed Dec. 9, 1966 5Sheets-Sheet 3 INVENTOR.

JOHN M. BAILEY ATTORNEYS United States Patent 3,381,615 DRIVING ANDTIMING MECHANISM FOR FUEL INJECTION PUMP John M. Bailey, East Peoria,Ill., assignor to Caterpillar Tractor Co., Peoria, IlL, a corporation ofCalifornia Filed Dec. 9, 1966, Ser. No. 600,450 3 Claims. (Cl. 103--2)This invention relates to fuel injection apparatus for internalcombustion engines and has particular reference to a new and improvedform of driving and timing mechanism therefor.

An object of the invention is to provide a simplified form of drivemechanism in which all of the main rotating members of the pump may bedriven directly off of the drive shaft without resorting to extensivecouplings which complicate the problem of providing proper timmg.

Another object of the invention is to provide a new and improved fuelinjection pump having variable timing means whereby the timing of theinjection by the pump may be varied during pump operation.

A further object is to provide an apparatus of the type set forthwherein the means for varying the timing of injection is embodied in thepump and does not require any external timing device.

Another object is to provide a distributor pump having a new andimproved drive means for imparting simultaneous reciprocation androtation to a pumping and distributing member.

Yet another object of the invention is to provide a novel centrifugalforce governing mechanism for a fuel injection pump.

Another object is to provide a new and improved device of the type setforth which is relatively compact and simple in construction andassembly, yet efiicient in operation.

Other objects and advantages of the invention will be apparent from thefollowing description taken in connection with the accompanyingdrawings. It will be understood that many changes may be made in thedetails of construction and arrangement of parts without departing fromthe scope of the invention as set forth in the accompanying claims, asthe preferred form of the invent-ion has been shown and described by wayof illustration only.

In the drawings:

FIG. 1 is a longitudinal view, partially in section, of a fuel injectionapparatus embodying the invention;

FIG. 2 is a sectional view taken on the line IIII of FIG. 3 is asectional view taken on the line III-III of FIG. 1;

FIG. 4 is a side elevation taken at line IV-IV of FIG. 3;

FIG. 5 is a view, partially in section, taken on the line VV of FIG. 1;

FIG. 6 is a sectional view taken on the line VIVI of FIG. 1;

FIG. 7 is a sectional view taken on the line VII-VII of FIG. 5; and

FIG. 8 is a sectional view showing a modified embodiment of theinvention.

Referring now to FIG. 1 of the drawing, there is shown a two parthousing 10 having the sections 12 and 14 thereof fastened together as bymeans of bolts 16. Section 14 of the housing is provided with a recess18 which receives a pump head generally indicated at 20. The insidediameter of the recess 18 and an external annular groove 22 formed onthe pump head define a fuel manifold 24 which comunicates with a fueltransfer pump (not 3,381,615 Patented May 7, 1968 shown) by means of aconduit 26. The pump head 20 is provided with a bore 28 which receives aplunger 30 for both reciprocal and rotational movement therein. The bore28 is connected to a series of passages 32 (only one of which is shown),each of which is connected by a fuel line 34 to a fuel valve for eachcylinder of the engine.

Fuel from the manifold 24 is free to flow through a fuel supply passage36 into the bore 28 upstream of the plunger 30. The plunger 30 isprovided with an axial passage 38 which intersects a radially drilledspill bore 48. An adjustable sleeve 42 is slidably received externallyof the plunger 30 for controlling the opening and closing of the spillbore 40. The sleeve and spill bore are located in a spill chamber 44which communicates with fluid passage 36 by means of a passage 46.

The quantity of fuel delivered on the injection stroke is determined bythe relative position of sleeve 42 to spill bore 40 after passage 36 hasbeen closed by axial movement of the plunger 30. During the pumpingstroke of plunger 30, the spill bore 40-is covered by the collar 42trapping the fuel therein. After the plunger passes passage 36 and whilespill bore 40 is covered, the pressure in bore 28 increases and forcesfuel from the bore to open a conventional spring loaded delivery valve48 permitting fuel to flow into a chamber 50. The fuel then flows fromthe chamber 50 into a connecting passage 52 and subsequently into anannular groove 54 formed externally of the plunger 30. Fuel flows fromthe groove 54 to a distributing slot 56 which is adapted to communicatewith each of the passages 32 in succession as the plunger 30 rotates.

As the spill bore 40 is opened to chamber 44, fuel is allowed to flowfrom the axial plunger passageway 38 into the chamber and out throughpassage 46. As a result, the pressure drops in bore 2-8 and the deliveryvalve 48 closes ending injection. Adjustment of sleeve 42 controls thequantity of fuel delivered to the fuel valves by varying the effectivepumping stroke of the plunger 30. The delivery valve 48 maintains aprescribed residual pressure in the fuel delivery passages and theconduits between the pump and the injectors during the period betweeninjections.

As shown in both FIGS. 1 and 2, a ball type governor is used to maintainengine speed. The governor comprises a carrier 58 secured to a driveshaft 60. The carrier 58 is provided with slots 62 which carry balls 64.The balls 64, being sensitive to centrifugal force as a result of theirweight and speed of rotation around the drive shaft 60, react against afixed ramp 66 which is secured to housing section 12 and a movable ramp68 which is axially slidable on a diameter 70 of housing member 14 whichis concentric with plunger 30. A pin 72 in member 14 engages a slot 74of ramp 68 and prohibits the ramp from rotating about diameter 70. Sucha novel centrifugal governing structure eliminates the need for thrustbearings normally associated therewith since the balls 64 also serve asthrust members.

As shown in FIGS. 1, 3 and 4, a yoke 76 is pivotally secured to housingmember 14 at 78 and is adapted to engage ramp 68 by means of a camsurface 80 formed thereon. A rod 82 is pivotally mounted on the upperend of yoke 76 at a point 84. FIGS. 6 and 7, in conjunction with FIG. 1,more clearly show the other end of the rod or shaft 82 which is providedwith a longitudinal slot 83 which slidably receives a pin 91 whichextends across the bifurcated end of member 90 and has a plate 85carried thereon. The plate 85 provides a retainer for one end of aspring 86, the other end of the spring engaging the raised annularshoulder 87 on rod 82. A second shoulder 88 is also formed on rod 82 forcontacting the stop 89 formed on housing member 14. The pin 84 ispivotally 3 mounted in bifurcated member 90 which in turn is secured atits upper end to a rotatable shaft 92 having a control lever 94.

I It will be noted that a link 96 is also mounted on the top of yoke 76.The other end of link 26 is pivotally attached to a lever Q8, whichlever is-fixedly secured on the upper end of a rotatable shaft (FIGS. 1and 6). The rotatable shaft 100 extends through both the body member 14and the pump head and is provided on its lower end with an eccentricallymounted pin 192 which engages an annular groove 104 formed in the collar42.

In operation, the lever 94 is moved counterclockwise which also rotatesbifurcated member 90 counterclockwise moving plate 85 to the right andcompressing spring 86 against a shoulder 87 and subsequently causingyoke 76 to pivot in a clockwise direction against the ramp 68. Movementof the yoke 76 toward ramp 68 results in counterclockwise rotation oflever 98 and shaft 160 through the link connection 96. When the shaft100 is rotated, the sleeve 42 moves axially along the plunger 31? due tothe eccentric connection 192. The yoke 76 continues to move in aclockwise direction until the cam surface 80 engages the ramp 68. Inthis position, yoke 76 has caused sleeve 42 to be adjusted to allow fora maximum effective stroke which results in maximum injection of fuelper stroke of the plunger 30. The plate will continue to compress spring86 until the shoulder 88 of shaft 82 abuts against the stop 89. In thisposition, ihedgovernor is set to allow the engine to run at full Asengine speed continues to increase and the centrifugal force of theballs 64 overcomes the balancing force of the spring 86, ramp 68 willmove yoke 76 in a counterclockwise direction. When this action occurs,link 96 causes lever 98 to move shaft 100 in a clockwise direction,thereby adjusting the sleeve 42 such that less fuel is injected andproper engine speed is maintained. The compression of the spring 86 willdetermine the speed of the engine by allowing the balls 64 to move ramp68 until the force on the balls is equal to the force of the spring,thereby adjusting sleeve 42 to a position which maintains a prescribedspeed established by the control lever 94.

In accordance with the invention, the driving and timing mechanismcomprises a drive shaft 60 having a radial bore extending therethroughfor receiving a camshaft 112. The camshaft 112 has a spur gear 114formed on one end which engages a stationary gear 116, preferably of theface or bevel type, which surrounds the drive shaft 66. Axial movementof the camshaft 112 in the bore 116 is prevented by the use of a thrustplate 118 which is bolted to the drive shaft 60 and engages a groove 120formed in the camshaft 112. As the shaft 60 is rotated by drive gear122, the camshaft 112 is forced to rotate about its own axis by theaction of its spur gear 114 meshing with face gear 116. As best shown inFIG. 2, the camshaft is provided with one or more lobes 124 which, uponrotation of the camshaft, force a roller 126 against the lower surfaceof a lifter 128 which carries the plunger 30 for axial reciprocalmotion.

The lifter 128 is carried in an axially extending bore 130 formed in oneend of the shaft 60. The lifter 128 is allowed to reciprocate in anaxial direction and is prohibited from rotational movement relative toshaft 60 by means of a pin 132 which engages a longitudinal slot 134formed in the lifter. The plunger 30 is directly connected to the driveshaft 60 for rotational movement therewith in the following manner. Apin 136 secures a spring retainer 138 to the shaft 60 and causes theretainer to rotate in unison with the shaft. The spring retainer 138 isprohibited from axial movement within the bore by a shoulder 140 formedin the bore 130 and a snap ring 142. The retainer 138 is provided with aslotted portion 144 which slidably receives a pin 146 which is pressedinto the plunger 30. This latter connection insures that the plunger 36rotates with the retainer 138 and 4 shaft 60 while still allowing theplunger to simultaneously reciprocate.

The retainer 138 also seats one end of a coil spring 148, the other endof which presses against a retainer 150 which is held upon the end ofplunger 30 by means of a shoulder 152. The spring 148 insures that theplunger 36 will be returned to its fill position after the cam lobes 124have moved out of engagement with roller 126. Thrust forces from thepumping load are imparted to the face gear 116 by a thrust bearingassembly located between a shoulder formed on the shaft 60 and saidgear.

It should be observed that the speed of the camshaft about its axis isdetermined by the ratios of the diameters of the spur gear 114 and theface gear 116. In the particular embodiment shown, shaft 6%) turns atone-half engine speed and a 4:1 gear ratio causes the camshaft 112'torotate at twice engine speed. Two cam lobes 124 are used for an eightcylinder, four cycle engine. It is to be understood that various engineconfigurations can be satisfied by varying the spur-face gear ratioand/or the number of lobes provided on the camshaft.

The drawings also disclose a means for lubricating the drive shaft,camshaft, and lifter assembly. Oil from a pump (not shown) enters apassage 164 and fiows into an annular groove 166 formed on the shaft 66,from whence it enters passages 168, 170 and 172. The passage 172 has asmall diameter orifice which communicates with the bore 110 and is usedto provide coolant and lubrication for the camshaft 112, in the area ofthe cam lobes 124. Passages 168 and 176 direct oil into annular grooves176 and 178 of camshaft bearings 189 and 182. Lubricant for the camshaft112 is provided by small diameter ports formed in the bearing grooves176 and 178. The annular groove 176 communicates with a passage 186which leads to an annular groove 188 formed in the lifter 128. As bestshown in FIG. 2, the lifter 128 is provided with a relief 190 on itsouter surface connecting with a passage 192 that directs oil to theroller 126. The passage 186 also permits lubrication between shaft 60and housing member 14. Oil drainage from bore 110 is provided by apassage 196 shown in FIG. 2 while drainage passages 198 and 200 (shownin FIG. 1) are provided to drain the housing.

FIG. 8 shows a modified embodiment of the pump drive mechanism wherebyvariable timing is achieved by changing the position of the face gear116' with respect to the drive shaft 60 during operation of the engine.A spring biased actuating piston 204, controlled by some means sensitiveto some desired engine variable such as engine speed or manifoldpressure, moves a pin 266 in a slot 208 formed in the face gear 116'.Movement of the pin 296 causes the face gear 116 to rotate about thecircumference of the drive shaft 60, thereby changing the angularrelationship of the camshaft 112 with respect to the drive train of theengine.

I claim:

1. In a device of the character described, a housing; a rotatable driveshaft extending into said housing and having a first bore extendingaxially inward from one end thereof; said first bore receiving acombination pumping and distributing member; a second bore extendingaxially through said drive shaft and communicating with said first borecentrally of said drive shaft; said second bore receiving a camshaft forrotation therein; lobe means formed on said camshaft for selectivelyaxially reciprocating said pumping and distributing member in said firstbore; first circumferential gear means formed on one end of saidcamshaft; and, second normally stationary gear means outward of saiddrive shaft and concentric therewith for engaging said first gear meansto cause rotation of said camshaft upon rotation of said drive shaft.

2. A device as described in claim 1 wherein actuating means are providedfor selectively rotating said second gear means during operation of saiddevice to vary the reciprocating cycle of said pumping and distributingmember.

3. Apparatus as set forth in claim 1 having in combina- References Citedtion therewith a centrifugal governor comprising a rotatable carriersecured near said one end of said drive shaft UNITED STATES PATENTS andhaving a plurality of spaced radially extending cir- 141,480 8/1873Archer 74-22 cumferential slots; each of said slots receiving aspherical 5 2 465 784 3/1949 Berlyn ball for radial movement therein;said balls normally in 309l231 5/1963 Giraud) 123 139 13 contact with apair of ramp members which cooperate to n define an expansible cagethereabout; one of said ramp members being fixed and the other of saidramp members DONLEY ING, Primary Exammel. being movable axially of saidcarrier but fixed against m- 10 V. EFNER Examiner tational movementtherewith.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,381,615 May 7, 1968 John M. Bailey' It is certifiedthat error appearsin the above identified patent and that said Letters Patent are herebycorrected as shown below:

Signed and scale 's 4th day of November 1969.

A 'st:

Ea ward M. Fletcher, Jr. Attgeggg Officer WILLIAM E. Commissioner ofPatents

1. IN A DEVICE OF THE CHARACTER DESCRIBED, A HOUSING; A ROTATABLE DRIVESHAFT EXTENDING INTO SAID HOUSING AND HAVING A FIRST BORE EXTENDINGAXIALLY INWARD FROM ONE END THEREOF; SAID FIRST BORE RECEIVING ACOMBINATION PUMPING AND DISTRIBUTING MEMBER; A SECOND BORE EXTENDINGAXIALLY THROUGH SAID DRIVE SHAFT AND COMMUNICATING WITH SAID FIRST BORECENTRALLY OF SAID DRIVE SHAFT; SAID SECOND BORE RECEIVING A CAMSHAFT FORROTATION THEREIN; LOBE MEANS FORMED ON SAID CAMSHAFT FOR SELECTIVELYAXIALLY RECIPROCATING SAID PUMPING AND DISTRIBUTING MEMBER IN SAID FIRSTBORE; FIRST CIRCUMFERENTIAL GEAR MEANS FORMED ON ONE END OF SAIDCAMSHAFT; AND, SECOND NORMALLY STATIONARY GEAR MEANS OUTWARD OF SAIDDRIVE SHAFT AND CONCENTRIC THEREWITH FOR ENGAGING SAID FIRST GEAR MEANSTO CAUSE ROTATION OF SAID CAMSHAFT UPON ROTATION OF SAID DRIVE SHAFT.